Identification and characterization of glycosyltransferases catalyzing direct xanthone 4 ‐C‐glycosylation in Hypericum perforatum

Xanthones are compounds with a diphenyl ether skeleton mainly found in plants and often glycosylated at carbon atoms. Although manyC-glycosyltransferases (CGTs) participating in flavoneC-glycosylation have been identified, MiCGT fromMangifera  indica, adding sugar to an open-chain benzophenone skeleton, is the only identified xanthone biosynthesis-related CGT. Here, we identified two CGTs fromHypericum  perforatum that add sugar to the closed-ring xanthone, but not benzophenone. These CGTs catalyze sugar transfer to the C-4 position of norathyriol (1,3,6,7-tetrahydroxyxanthone) to form isomangiferin (1,3,6,7-tetrahydroxyxanthone 4-C-glucoside), a major xanthoneC-glucoside. This is the first study to report CGTs that mediate the directC-glycosylation of xanthone.
Source: FEBS Letters - Category: Biochemistry Authors: Tags: Research Letter Source Type: research